This application is based on Patent Application No. 2001-346330 filed Nov. 12, 2001 in Japan, the content of which is incorporated hereinto by reference.
1. Field of the Invention
The present invention relates to a KGD carrier, more particularly to a KGD carrier having the structure around the substrate thereof improved and an IC socket for mounting the KGD carrier.
2. Description of the Related Art
In the conventional way, when subjecting a non-package chip (or die) satisfying the given specifications, i.e., a KGD (Known Good Die), to the burn-in test, it has been a common practice that the KGD to be tested is once mounted on a special carrier, and the carrier mounted with the KGD is then mounted on an IC socket. Then, the IC socket is incorporated into a test board to undergo the burn-in test.
The structure of a conventional KGD carrier for mounting the KGD will be described briefly referring to FIG. 5. FIG. 5 shows a cross-sectional view of the carrier mounted with an IC chip.
The KGD carrier 10 comprises a carrier retaining member 20 and a carrier base assembly 30.
The carrier retaining member 20 comprises a cover 21, a chip retaining member 22, a coil spring 23 and a steel ball 24 so that the IC chip 40 placed on the carrier base assembly 30 can be held elastically.
The carrier substrate 30 comprises a carrier body 31 including a latch 36 for locking the carrier retaining member 20 with the carrier base assembly 30, a substrate (a contact seat) 32 as being a printed-circuit board, an elastomer frame 33, an elastomer 34 as being a cushion to be placed in the elastomer frame 33, and a carrier base 35. The carrier body 31, the substrate 32, the elastomer frame 33 and the carrier base 35 are integrated into a single body by using screws or the like (not shown) to form a carrier base assembly 30. The film-like substrate 32 needs to be kept open so that the pad 32a placed therearound can electrically be connected with the contact of the IC socket. Therefore, in order to prevent the substrate 32, especially the peripheral portion thereof, from becoming saggy, the substrate 32 is previously bonded to the elastomer frame 33 (or to the carrier base 35 if the elastomer frame 33 is omitted) or to the carrier body 31.
The IC chip 40 is mounted on the carrier 10 in a fashion described below. First, while the carrier retaining member 20 is removed, the IC chip 40 is placed on the substrate 32. Subsequently, the carrier retaining member 20 is used to press the IC chip 40 inward evenly and elastically until coming into close contact with the substrate 32, thereby enabling the IC chip 40 and the substrate 32 to be electrically connected with each other. Further, the latch 36 is made to engage with a cover 21 of the carrier retaining member 20 to complete the mounting of the IC chip 40 as illustrated in FIG. 5.
The carrier 10 mounted with the IC chip 40 is further mounted on an IC socket 50 as is shown in FIG. 6.
The IC socket 50 comprises an operating cover 51, a socket base 52 and a contact 53 which includes a contact portion 53a, an elastic portion 53b, a stationary portion 53c and a terminal portion 53d. The IC socket 50 is designed so that the contact portion 53a of the contact 53 moves back away from and forth toward a pad 32a, which is formed on the substrate 32 of the carrier 10 mounted on the IC socket 50, as the operating cover 51 moves up and down.
In order for the carrier 10 to be mounted on the IC socket 50, the operating cover 51 needs to be pushed downward to make the contact portion 53a of the contact 53 to retreat. Then the carrier 10 enables to be positioned and placed on a mounting base 52a of the socket base 52. Subsequently, when the downward pushing force of the operating cover 51 is released, the operating cover 51 rises because of the restoring force of the spring (not shown). Then, the contact portion 53a of the contact 53 returns to its original position and abuts the pad 32a of the substrate 32 of the carrier 10. Consequently, the substrate 32 (i.e., the IC chip 40) is electrically connected with the contact 53.
The IC chip 40, mounted on the IC socket 50 through the carrier 10 in the previously described manner, is then set in a test board (not shown) to undergo the burn-in test.
As described previously, in the case of the conventional carrier 10, the substrate 32 is bonded to the elastomer frame 33 and the carrier base 35 or the carrier body 31, so that, for example as shown in FIG. 6, the substrate 32 is in contact with the contact 53 of the IC socket 50 only at one point, which may result in unstable electrical connection.
In consideration of the point discussed above, the present invention is designed to provide a KGD carrier capable of obtaining sure electric connection by enabling the substrate of the KGD carrier base assembly and the contact of the IC socket to contact with each other at 2 points.
In order to attain the above object, the KGD carrier according to the present invention is designed to hold the IC chip by means of the carrier retaining member and the carrier base assembly. The carrier base assembly comprises the carrier body, the carrier base and the substrate. The carrier body is provided with grooves, which are located opposing pads formed around the substrate, to permit the in-and-out motion of contacts of the IC socket. The carrier base is also provided with grooves, which are located opposing the pads formed around the substrate, to permit the in-and-out motion of the contacts of the IC socket. The substrate is interposed between the carrier body and the carrier base to enable the pads and the corresponding contacts to be connected electrically with each other.
The above and other objects, effects, features and advantages of the present invention will become more apparent from the following description of embodiments thereof taken in conjunction with the accompanying drawings.